Jiang Yi had indeed reached the Yi Clan's four regions. However, he had arrived at the Buddha Light Region, south of the Buddha Region. At this time, there was indeed an army attacking one of the Yi Clan's cities.
This was a big city in the Buddha Light Region. The citizens of the city had long fled; there were only a few hundreds of thousands of soldiers left as well as some elders who refused to leave their hometown. The fighting in the city was not that furious; the battle was severely imbalanced.
The Yi Clan only had four hundred thousand troops without a single Demigod; among them were only one hundred thousand Heaven Monarchs with the rest being of the Vajra Realm. On the other hand, two Demigods were leading the approaching army. There were tens of thousands of peak-stage Heaven Monarchs while the army was around three million in size.